Optophone



July 5, 1949 J. A. cAsl-uu. 2,475,444

' OPTOPHONE I Filed Sept. 18, 1946 mm ran UM QM Patented July 5, 1949OP'IOPHONE James Andrew Cashin, Liverpool, England Application September18, 1946, Serial No. 697,821 In Great Britain September 27, 1945 6Claims.

This invention relates to so-called optophones or apparatus forrepresenting printed characters as combinations of sounds. Suchapparatus enables a blind person to read ordinary printing by ear.

As previously proposed a plurality of light beams each modulated at adifferent frequency has been used to eifect scanning of parts ofsuccessive let? ters in a word or line, the resultant reflected lightbeing detected by photoelectric means connected to electric waveresponsive sound generating means. A disadvantage which has presumablyrendered this prior contruction impracticable or unsuccessful is to befound in the minuteness and extreme precision required in the projectionof the various beams of modulated light in correct mutual relationship.This invention seeks to avoid these disadvantages.

According to this invention, a magnified image of part or all of thetype is projected on to a perforate screen, mask or other image dividingand selecting means, before modulation and detection, a singlephotoelectric means being used to detect all the modulated lightcomponents.

The image is magnified and cast relatively sharply upon a perforatescreen through dilferent perforations through which pass selected lightcomponents. The selected increments are then each modulatedcharacteristically, conveniently by a rotary plate having a plurality ofcoaxially disposed groups of slo The apparatus may be renderedblack-sounding by simultaneously projecting an image from a white orneutral blank object, simultaneously dividing said image anddifierentially modulating each increment of the blank image with respectto a corresponding increment of the printed character image.

This may be effected by spacing the corre+ sponding selection holes atany interval on the mask, said interval corresponding exactly to thelength of the corresponding modulator slit and land between successivecorresponding modulator slits.

The invention will be described further by way of example with referenceto the accompanying drawings in which:

Figure 1 is a fragmentary side elevation of a modulator disc or sector.

Figure 2 is a fragmentary side elevation of a perforate screen or mask;

Figure 3 is a diagrammatic apparatus.

Referring to the drawings, the paper to be plan of one form of read isplaced upon a plane or curved surface a capable of movement in twodirections; one direction being in line with the lines of print, theother being across them. Light from lamps b and bl is directed partlyonto the paper and partly onto a tongue t made of white material so asto give a similar reflection to paper. The characters are moved acrossthis light in turn. Light reflected from the paper andtongue iscollected by lens c and a moving image of each character is thrown ontothe screen d, which carriesa number of holes I and g. A disc e parallelto the screen has a number of coaxially disposed groups of, i. e., ringsof circumferential slots (with radial edges'll and is rotated by anelectric motor at a speed which may be varied at will.

Holes 1 and g in the screen 01 are located at radial distances such asto coincide with rings of slots in disc e the pair of holes at eachradius in the screen d being set at centres equal to the length of thecorresponding slots in the disc 6. In each ring, in disc e, the spacebetween a pair of slots is equal to the length of a slot. The ratios ofthe number of slots in each ring are re lated in a manner similar to therelationship be tween the frequencies of a series of notes in a musicalscale. A photo-electric cell h is placed in line with the screen anddisc, so that light projected through the holes in the screen, andthrough the slots in the rotating disc, falls on its cathode. Thephoto-cell is connected through an amplifier k to a loudspeaker l orheadphones.

Light from the printed sheet is projected onto and through holes and isvaried by the image of the printed character as it moves over them,whilst, at the same time an unvarying light reflected from the tongue itpasses through holes When there is no printed character under the lighton the page, an equal amount of light is projected through holes and g.This light is interrupted by the slots in the disc e in such a way as toallow light to pass through holes ,1 and g alter nately, decreasing inone at the same rate at which it increases in the other, thus a steadyunvarying light falls on the photo-cell and no sound is heard.

When a printed character causes variation in the light passing throughholes I, the light reaching the proto-cell becomes modulated in such away as to give rise to a series of musical notes, each printed characterhaving a characteristic tune which is learned by the operator.

This is effected as follows: Reflected beams of light are projected onto the holes j and g respectively. That beam coming from the tongue a isprojected on to the holes 9 while the other beam coming from the letterto'be"rea'd is projected on to the holes f. The relative positions ofthe holes ,1 and g are so chosen with respect to the width of theapertures of the holes that the i1} lurninat ion of the photo-electriccell 71 is constant when both beams are of equal strength, but when thebeam reflected by the letter is weaker, owing to absorption by the blackink, this beam is interrupted so many times per second, that a currentcorresponding to a musical note is produced in the 3 photo-electriccell. Different portions of the beam cor-responding to different partsof the letter, each produce its characteristic note, so that the letteras a whole can be recognized.

To allow for different reflecting indices of different papers, theintensit or direction of the light reaching holes 1 and 9 ma be variedby adjusting the light from lamps b and bl. In an alternative form ofconstruction, one lamp only, possibly with two filaments, may be used.

Print of different sizes may be read by adjusting the optical distancebetween the page and the screen d, the lenses being automatically keptat the correct focus. A reflecting prism or prisms may be interposedbetween lens 0 and screen d, to change the direction of the beam, and/orto shorten the actual distance between these points whilst maintainingthe greater optical distance. By rotating one of the prisms through asmall angle, the beam may be rotated to enable sloping characters suchas italics or handwriting to be read. Varying the optical distance maybe effected by moving one of the prisms towards or away from thescreend.

The slots in disc e are made wider in a radial direction than the holesin the screen cl, and the screen may be rotated to present differentsets of holes for reading different type, such as italics, or characterswith thicker or thinner lines.

Holes 1 in screen 11 may be radial to sound a musical chord or staggeredto sound the notes of the musical scale in succession.

In order to reduce the size of the light and/or to spread it more evenlyover the cathode of the photo-cell a lens 7' may be interposed betweenthe rotating disc e and the photo-cell.

Whilst the invention is especially applicable for representation ofprinted characters produced by inked type it is obvious that suchprinted characters need not necessaril have been produced by inked type.The word printed in the description and claims is intended to includecharacters produced photographically, lithographically, by the use ofhand writing instruments and otherwise.

I declare that what I claim is:

1. An apparatus for representing printed characters as combinations ofsound, comprising image dividing and selecting means for producing aplurality of image components, means to project an enlarged moving imageof at least part of a character onto said dividing and selecting means,means for distinctively modulating each component, and a singlephoto-electric means for detecting the modulated components.

2. An apparatus, for representing printed characters as combinations ofsound, comprising image dividing and selecting means for producing aplurality of image components, means to project a moving image of atleast part of a character onto said dividing and selecting means, meansfor intermittently masking each component at distinctive frequency asingle photoelectrio means responsive to light from the variousintermittently masked components, electroacoustic means for producingsound in accordance with audio frequency electric currents, and electriccircuit means connected to said photoelectric means and to saidelectro-acoustic means whereby audio frequency electric currents arecaused to energize said electro-acoustic means responsive to amplitudeand frequency of light 4 received from said intermittently maskedcomponents by said photoelectric means.

3. An apparatus, for representing printed characters as combinations ofsound, comprising a screen having a plurality of perforations therein,means to project an enlarged image of at least part of a character ontosaid mask plate so that components of light from the enlarged image canpass through the perforations, means for distinctively modulating eachcomponent with a distinctive frequency, and means for producing soundsresponsive to the frequencies and amplitudes of the respective modulatedcomponents.

4. An apparatus, for representing printed characters as combinations ofsounds, comprising a.

screen having two sets of perforations therein,, means to project anenlarged moving image of.

at least part of a character onto said screen so that selected lightcomponents thereof pass through one set of perforations, means toproject light of background intensity onto said screen so that selectedcomponents thereof pass through the other set of perforations; means forsimultaneously differentially modulating each component from the firstset of perforations with respect to a component from the second set ofperforations with a distinctive frequency, and means for detecting thedifferentially modulated pairs of components.

5. An apparatus, for representing printed characters as combinations ofsounds, comprising means for projecting a moving image of a character,means for projecting an image from a neutral blank object of backgroundintensity, a screen having two sets of perforations therein forreceiving said images each in the region of one set of perforations, arotary sector modulator plate having groups of arcuately extending slitsand lands of equal interval each group being substantially aligned tomodulate by intermittent masking light from pairs of perforations in thescreen, whereby the said images are divided by the screen and selectedlight components from the character image are modulated differentiallywith respect to the blank image components, and means to detect all themodulated light components and to product sounds corresponding infrequency to the modulation frequency of each modulated component and ofintensity corresponding to the amplitude of each modulated component.

6. In apparatus for producing sounds responsive to distinctivemodulation frequencies of light components from selected parts of acharacter, the improvement comprising means to produce an enlarged imageof the character, means to divide said enlarged image into components,and means tomodulate each component distinctively.

JAMES ANDREW CASHIN.

REFERENCES CITED The following referenlces are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,628,077 Tarbox May 10, 19271,986,977 Wainright Aug. 7, 1934 2,035,773 Thomas Mar. 31, 19362,137,888 Fuller Nov. 22, 1938 2,332,469 Reisz Oct. 19, 1943 2,403,997Potter July 16, 1946

